Hawking radiation

I must admit I only wrote this post because I thought the title would be amusing. Was I right? Time will tell. Via a variety of sources some of whom I ignored, I find the great physicst saying President Trump’s decision to pull out of the Paris climate change accord could lead humanity to a tipping point, “turning the Earth into Venus.”1 That, as we all know, is bollocks. Or in JA’s more measured terms, “I don’t believe such hyperbole is useful”. Don’t mince your words, man, you’ll never get onto a high-status Red Team that way.

My Hawking claim-to-fame is that I was cycling over the Garret Hostel Lane bridge, which is rather hump-backed, and nearly ran over his wheelchair coming the other way. Fortunately for the sake of future GW hyperbole I swerved in time.

I wasn’t terribly impressed by his I fear evolution has inbuilt greed and aggression to the human genome. There is no sign of conflict lessening, and the development of militarised technology and weapons of mass destruction could make that disastrous. The best hope for the survival of the human race might be independent colonies in space. The greed-n-aggression is reasonable, but it is far from the only thing to consider, as should be obvious when you consider that we aren’t all dead. And quite why floating off into outer space should cure the G-n-A I don’t know2.

Incidentally, not everything The Great Man said was wrong; By denying the evidence for climate change, and pulling out of the Paris Climate Agreement, Donald Trump will cause avoidable environmental damage to our beautiful planet, endangering the natural world, for us and our children seems quite reasonable. And Trump genuinely is a bozo.

Notes

1. Checking with the Beeb interview, it looks like he actually said this and has not been distorted by paraphrase.

2. As we should be fairly familiar with by now, great eminence in one field doesn’t carry over into valuable expertise in another. There’s probably a pithier way of saying that.

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22 thoughts on “Hawking radiation”

WMC writes: “As we should be fairly familiar with by now, great eminence in one field doesn’t carry over into valuable expertise in another. There’s probably a pithier way of saying that.”

It probably ought to be a sub-category of Dunning-Kruger. Like, D-K type A is someone who’s consistently incompetent across a wide variety of domains and incorrectly believes they are an expert. D-K type B is someone who has genuine expertise in one or more domains, and incorrectly believes that expertise translates into other domains.

In some people’s perception, the ultimate authority on all science stuff is a famous scientist. The scientist’s qualifications don’t come into it. The person is a famous buff, hence must be smart, hence ‘knows’ stuff we don’t understand.

[Well, that’s not too unreasonable; certainly it is understandable; Joe Public is not equipped to evaluate the credentials of different branches of science. What is needed to stop this going off track, then, is that when Famous Scientist says something silly, actual-real-scientists need to tell said FS that they’ve said something silly, and the FS needs to listen. This would presumably happen behind the scenes. In the old days, of course, it would happen discretely in the SCR but now the colonials do science it’s a bit harder -W]

C-ball has a long and digraceful tradition of manipulating, cajoling, encouraging and perverting once honourable scientists to say some titbit that it can then latch on to. Reveille, Freeman Dyson, etc. It’s the closest they ever get to an argument from authority, which may be a fallacy, but that doesn’t bother the average MITS.
So, whether scientists understand the limits of Hawking’s possible contribution, in the public sphere, what matters that the great man has spoken, and he says DT is a loon, the rest is still too science-y to cope with.
So, lets get lots of really famous scientists and Nobel prizewinners to say whatever they want to about climate change, so long as it is vaguely sensible.

William, what is needed is for journalists when they get a statement from a FS to check if it makes any sense, and if it doesn’t avoid publishing it, even if it would make great click bait.

[Yeeesss… though I have some sympathy for the journos, who don’t know science after all. Should they expect FS to get it right? I suppose they really should have recognised “like Venus” for a clearly controversial statement that needed someone to ask. But then again: you’re a climate scientist, not a top-rank-famous one, but the sort that journos contact for fact-checking. A journo contacts you and says “FS says ‘Venus'”. Do you say “that’s bollox”? No, probably not (unless you’re me, or JA :-). You equivocate. And so journo doesn’t get a clear steer. Aand… of course, not reporting the most “interesting” statement in FS’s talk could be considered poor reporting; though they could follow it with “BTW this is bollox”. Oh, I don’t know… the blame is FS’s, for being a bozo -W]

“Incidentally, not everything The Great Man said was wrong; By denying the evidence for climate change, and pulling out of the Paris Climate Agreement, Donald Trump will cause avoidable environmental damage to our beautiful planet, endangering the natural world, for us and our children seems quite reasonable. And Trump genuinely is a bozo.”
True he is a bozo but even bozo’s can be right twice a day.
Trump’s pulling out could also cause avoidable environmental improvement but you fail to mention this proving that facts should not get in the way of a good argument once again.
More CO2, more trees,

[Not obviously, no. You need to be careful of what the CO2-is-plant-food tell you; not everything that Idso says is true -W]

more build up of future fossil fuel deposits for future generations.

[That last is silly -W]

Trees are not environment, William?
Putting CO2 back in the ground naturally is not admirable?
Oh well then, you win.

“Hawking is taking some rhetorical license here,” climate scientist Michael Mann, at the Pennsylvania State University, told Live Science in an email. “Earth is further away from the sun than Venus and likely cannot experience a runaway greenhouse effect in the same sense as Venus — i.e. a literal boiling away of the oceans. However Hawking’s larger point — that we could render the planet largely uninhabitable for human civilization if we do not act to avert dangerous climate change — is certainly valid.”

Or rhetorical license, even? The Ramirez et al paper provided by JCH reckoned that we’d have to burn all fossil fuel reserves instantaneously to reach an atmospheric CO2 concentration capable of making the planet largely uninhabitable for human civilization. (They do say that if seabed methane hydrates joined the party we wouldn’t need to burn everything to make the planet uninhabitable, but I thought that possibility had been ruled out.)

As lamented at Eli’s Poor Hawking has been having a bad year- he flies to Hollywood to launch Starshot, but it comes unstuck when folks complain about the lack of terminal guidance, the inhomogeneity of the interstellar medium and radiation damage levels that would do credit to a CERN beamstop.

Then he gets dragged into the Climate Wars by RC commentors like McDonald:

“I am not a denialist. In fact I am just a climate model critic and a catastrophist, like Professor Stephen Hawking. Only, he’s got it wrong. We will not follow Venus’s example because we already have. The surface temperature on Venus soared until the surface melted and suphur clouds prevented temperatures rising further. The same thing happened on Earth at the end of the Younger Dryas when temperatures in Greenland soared by 20C, after the sea ice in the GIN Seas melted and clouds grew to limit our temperature rise. A similar event will happen when the Arctic sea ice melts, and another irrevocable change will occur.”

The focus on whether we can burn enough go directly to a hyperthermal is in error since we have the example of past ones (PETM, MECO and a couple smaller) that required zero such. So the actual question of interest is whether our burning can trigger a similar chain of events.

In brief, yes. Plausible sequence: Very rapid (as these things go) loss by fire of boreal carbon (permafrost, peat, trees), followed by similar loss of the tropical forests, followed by the ocean warming enough to light off significant methane hydrates.

Hansen et al. (2013) notes that the beginning pace of the Eocene hyperthermals was probably conditioned by the relative slowness of the Milankovitch changes thought to have set them off. We’re forcing things ever so much more quickly, so there’s potential for the tropical phase of the process to kick in early.

DA says the hydrates aren’t a short-term threat, but are a longer-term one once the oceans warm up enough. Hard to know how long that will really take, but the earlier phases are enough for effects like rendering the tropics uninhabitable (and a long parade of other horribles).

On the plus side, it’s not clear that the boreal contains as much carbon as the austral did in the Eocene, so maybe that phase will be milder. OTOH it’s already started lighting off (check out recent fire and lightning trends there) even while we continue to add forcing, so maybe not milder.

Melting ice sheets will definitely slow things down somewhat, so luckwarmers everywhere can pin their hopes on that..

The problem with the whole ‘greed and aggression’ thing is that moving it into space merely opens up a whole new vista of doomsday weapons, mainly based around throwing rocks at orbital-to-relativistic velocities.

In any case, 50 years ago NATO was planning on defending West Germany using a wide variety of battlefield nuclear weapons. We have managed to draw back from that position a bit.

The Warsaw Pact had enough to require parking some as far east as Afghanistan, not that NATO much minded, as the Afghans were on our side , which we have since learned is generally the better side to have them on

Red team? Perhaps there should a red team, a white team and a blue team. The white team can present the consensus view, the red team can argue a more optimistic view, and the blue team can argue a more pessimistic view.

CIP, 4 gya irradiance was about 33% less than present, Current Venus insolation being 2601 w/m^2 vs. 1361 for Earth, it couldn’t ever have been less. Add to that the reduced gravity and Venus starts to sound doomed from the start.

I don’t know if there’s an answer to when it went runaway, but my guess would be early.

Given that the PETM didn’t result in a runaway on Earth, it seems highly unlikely that could happen in the present even with ~1% greater insolation.